Observed active energy, comparative data

This major discrepancy almost certainly results from the failure in the assumptions involved in the treatment. In particular, the observed sensitivities of activation energies to small changes in bond length, in this and in many other systems where the sensitivity parameter has been measured, are far greater than can be accounted for by this treatment. (Compare the slopes of the solid and broken lines of Fig. 28 in the region of the data points.)... 

Computed results from this model are compared to actual kiln performance in Table VI and the operating conditions taken from kiln samples are given in Table VII. There are no unit factors or adjustable parameters in this model. As with the explicit model, all kinetic data are determined from laboratory experiments. Values of the frequency factors and activation energies are given in Table VIII. Diffusivity values are also included. The amount of fast coke was determined from Eq. (49). With the exception of the T-B (5/12) survey, the agreement between observed and computed values of CO, CO2, and O2 is very good considering that there are no adjustable parameters used to fit the model to each kiln. In the kiln survey T-212/10, the CO conversion activity of the catalyst has been considerably deactivated and a different frequency factor was used in this simulation. 

Hydrogen abstraction from propan-2-ol and propan-2-ol- /7 by hydrogen and deuterium atoms has been studied by pulsed radiolysis FT-ESR. A secondary kinetic isotope effect was observed for H (D ) abstraction from the C—H (C—D) bonds. The results were compared with ab initio data. In similar work, the kinetic isotope effects in H and D abstraction from a variety of other alcohols in aqueous solvents have been measured. It was found that, compared with the gas phase, the reactions exhibit higher activation energies in agreement with the ability of solvation to decrease the dipole moment from the reactant alcohol to the transition state. 

One exception [124] claims that, for the description of the experimental data obtained at high pressures, it is not necessary to change the kinetic model constructed on the basis of the data obtained at 10 8 to 10 7 Torr. (Only the activation energy for the CO desorption was decreased from 34 to 24.5 kcalmol 1.) This claim does not seem to be confident since the discussed kinetic model was only a unit in the model for the catalytic re-oxidation of CO and hydrocarbons. Experimental and calculated data were only compared on the basis of the observed values, i.e. temperature and the amount of unreacted CO in the output. 

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